1. Field of the Invention
The present invention relates, to fuel vapor control devices used mainly for an internal combustion engine installed on a vehicle.
2. Description of the Related Art
A conventional fuel vapor control device is shown in Japanese Laid-Open Patent Publication No. 11-34675. The fuel vapor control device disclosed in the Publication No. 11-34675 includes a fuel tank for storing fuel, a canister for adsorbing fuel vapor produced in the fuel tank, an evaporation path for communicating between the fuel tank and the canister, and a pressure regulating valve for opening and closing the evaporation path. Specifically, the pressure regulating valve closes the evaporation path when pressure inside the tank is less than a set value, and opens the evaporation path when the pressure inside the tank is equal to or higher than the set value. Apart from the fuel tank, a variable volume container (a bladder type subsidiary chamber constituted by bellows) is connected via a communicating path to inside of the fuel tank at above of fuel level. The volume of the variable volume container may change according to increase or decrease of the amount of the fuel vapor produced within the fuel tank. Due to this, the change of the volume of the variable volume container may absorb the fluctuation of the pressure inside the tank according to the increase or decrease of fuel vapor inside the fuel tank. Accordingly, the amount of the fuel vapor to be ejected into the canister can be reduced.
In the conventional fuel vapor control device, separately from the fuel tank, the volume variable container and the communicating path connected to the volume variable container are necessary for inhibiting the amount of the fuel vapor to be ejected to the canister. Due to this, the constitution of the fuel vapor control device has been inevitably complex.
Therefore, there has been a need for a fuel vapor control device that has a simpler constitution.